Degradable filter element for smoking article

ABSTRACT

A filter material configured for use as a filter element of a smoking article is provided, the filter material including at least one segment of fibrous tow having a plurality of superabsorbent objects dispersed therein, the superabsorbent objects comprising a starch material. Exemplary starch materials include naturally-occurring starch, hydroxyalkylated starch, starch esters, ionically modified starch, oxidized starch, hydrolyzed starch, plasticized starch, gelatinized starch, grafted starch, crosslinked starch, transglycosylated starch, starch ethers, and mixtures thereof, as well as blends of starch with other polymers. Filter elements and smoking articles, such as cigarettes, that contain the filter material are also provided. A method of preparing polymer fibers for use in filter elements is also provided, the method including adding the starch material to a fiber precursor solution prior to fiber extrusion or dry-blending the starch material with the polymer material to be formed into fibers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application which claims priorityto U.S. provisional application Ser. No. 61/360,201, filed Jun. 30,2010, which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to products made or derived from tobacco,or that otherwise incorporate tobacco, and are intended for humanconsumption, and in particular, to filters for cigarettes. The inventionis directed to additives for filter elements configured for increasingthe rate of degradation.

BACKGROUND

Popular smoking articles, such as cigarettes, have a substantiallycylindrical rod-shaped structure and include a charge, roll or column ofsmokable material, such as shredded tobacco (e.g., in cut filler form),surrounded by a paper wrapper, thereby forming a so-called “smokablerod” or “tobacco rod.” Normally, a cigarette has a cylindrical filterelement aligned in an end-to-end relationship with the tobacco rod.Typically, a filter element comprises plasticized cellulose acetate towcircumscribed by a paper material known as “plug wrap.” Certain filterelements can incorporate polyhydric alcohols. Typically, the filterelement is attached to one end of the tobacco rod using a circumscribingwrapping material known as “tipping paper.” It also has become desirableto perforate the tipping material and plug wrap, in order to providedilution of drawn mainstream smoke with ambient air. Descriptions ofcigarettes and the various components thereof are set forth in TobaccoProduction, Chemistry and Technology, Davis et al. (Eds.) (1999). Acigarette is employed by a smoker by lighting one end thereof andburning the tobacco rod. The smoker then receives mainstream smoke intohis/her mouth by drawing on the opposite end (e.g., the filter end) ofthe cigarette, until the tobacco rod is partially or completelyconsumed, after which the remaining cigarette portion is discarded.

The discarded portion of the cigarette rod is primarily composed of thefilter element. In general, cigarette filters include solvent crosslinked cellulose acetate fiber bundles wrapped in two layers of paper.The first layer of paper, often referred to as plug wrap, holds thefiber bundle together in a rod form and may include a glue line toanchor the fiber bundle to the plug wrap paper; the second layer, oftenreferred to as the tipping, is fully adhered to the plug wrap andattaches the filter tube to the wrapping material surrounding thecigarette's tobacco rod. Cigarette filters are slow to degrade ordisperse in the environment. This is generally attributed to the tightlybound nature of the filter plug's design which is configured to providea specified filtering effect, but which insulates the majority of thefilter from environmental effects upon disposal. Studies have shown thatonce the paper layers (e.g., plug wrap and tipping material) have beenfully breached and the cellulose acetate fibers opened and exposed toenvironmental effects, the degradation and dispersion of the filterelements will progress at a much accelerated rate, rather than takingmonths or even years to degrade.

A number of approaches have been used in the art to promote an increasedrate of degradation of filter elements. One approach involvesincorporation of additives (e.g., water soluble cellulose materials,water soluble fiber bonding agents, photoactive pigments, or phosphoricacid) into the cellulose acetate material in order to accelerate polymerdecomposition. See U.S. Pat. No. 5,913,311 to Ito et al.; U.S. Pat. No.5,947,126 to Wilson et al.; U.S. Pat. No. 5,970,988 to Buchanan et al.;and U.S. Pat. No. 6,571,802 to Yamashita. In some cases, conventionalcellulose acetate has been replaced with other materials, such asmoisture disintegrative sheet materials, extruded starch materials, orpolyvinyl alcohol. See U.S. Pat. No. 5,709,227 to Arzonico et al; U.S.Pat. No. 5,911,224 to Berger; U.S. Pat. No. 6,062,228 to Loercks et al.;and U.S. Pat. No. 6,595,217 to Case et al. Incorporation of slits into afilter element has been proposed for enhancing biodegradability, such asdescribed in U.S. Pat. No. 5,947,126 to Wilson et al. and U.S. Pat. No.7,435,208 to Garthaffner. U.S. Pat. No. 5,453,144 to Kauffman et al.describes use of a water sensitive hot melt adhesive to adhere the plugwrap in order to enhance biodegradability of the filter element uponexposure to water. U.S. Pat. No. 6,344,239 to Asai et al. proposes toreplace conventional cellulose acetate filter elements with a filterelement comprising a core of a fibrous or particulate cellulose materialcoated with a cellulose ester to enhance biodegradability. Each of thesereferences is incorporated herein by reference.

There remains a need in the art for a smoking article filter exhibitingenhanced environmental degradation properties, particularly where thefilter can be manufactured with only minor modification of conventionalfilter rod production equipment.

BRIEF SUMMARY

Embodiments of the present invention relate to a smoking article andassociated methods, and in particular, a rod-shaped smoking article(e.g., a cigarette). The smoking article includes a lighting end (i.e.,an upstream end) and a mouth end (i.e., a downstream end). A mouth endpiece is located at the extreme mouth end of the smoking article, andthe mouth end piece allows the smoking article to be placed in the mouthof the smoker to be drawn upon. The mouth end piece has the form of afilter element comprising a fibrous tow filter material. The fibrous towfilter material may incorporate an effective amount of a degradablestarch material (or other degradable polymer material) configured forincreasing the rate of degradation of the filter material upon disposal.Dispersal of a degradable material throughout the fibrous tow canenhance degradation by creating voids within the fibrous tow as thedegradable material decomposes, thus increasing available surface areawithin the fibrous tow for contact with the environment.

In one aspect, the invention provides a filter material configured foruse as a filter element of a smoking article, comprising at least onesegment of fibrous tow (e.g., cellulose acetate tow or polyolefin tow,or a combination thereof) including at least one (up to and potentiallyincluding a plurality of) superabsorbent object(s) dispersed therein(including being disposed within or between individual fibers of thefilter material), the superabsorbent object comprising a superabsorbentmaterial, the volume of which increases when it is exposed to water orother liquid. Exemplary superabsorbent materials may include one or moreof polyacrylic acid sodium salt (a/k/a sodium polyacrylate),polyacrylamide copolymer, ethylene maleic anhydride copolymer,cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymers,cross-linked polyethylene oxide, various hydrogels, and starch-graftedcopolymer of polyacrylonitrile, or any other suitable superabsorbentpolymer or non-polymeric material that will volumetrically expand uponcontact with material, such as—for example—water, that may commonly belocated in cigarette filter disposal locations, and mixtures thereof.

The invention also provides filter elements for smoking articles such ascigarettes, wherein the filter element comprises one or more segments offibrous tow filter material as described herein. For example, the filterelement can comprise a first segment of fibrous tow filter material anda second segment of fibrous tow filter material, wherein the firstsegment of fibrous tow filter material comprises a superabsorbentmaterial as described herein and the second segment is devoid ofsuperabsorbent material.

In another aspect, the invention provides a cigarette comprising atobacco rod having a smokable filler material contained within acircumscribing wrapping material and a filter element connected to thetobacco rod at one end of the tobacco rod, the filter element comprisingat least one segment of fibrous tow having at least one superabsorbentobject dispersed therein.

In yet another aspect, the invention provides a method of preparing acigarette filter having a superabsorbent material disposed therein.Methods for including a superabsorbent material into a smoking articlefilter may include but are not limited to: capsule insertion technology,pellet insertion technology, thread insertion technology using ahydrogel or other superabsorbent polymer or other material formed into athread/strand or by adhering grains of hydrogel to a carrier thread,sprinkling of grains into tow band, and/or inclusion into filter towwith a plasticizer.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to assist the understanding of embodiments of the invention,reference will now be made to the appended drawings, which are notnecessarily drawn to scale. The drawings are exemplary only, and shouldnot be construed as limiting the invention.

FIG. 1 is an exploded perspective view of a smoking article having theform of a cigarette, showing the smokable material, the wrappingmaterial components, and the filter element of the cigarette;

FIG. 2 is a cross-sectional view of one embodiment of a filter element;

FIG. 3 is a cross-sectional view of another embodiment of a filterelement;

FIG. 4A is a cross-sectional view of another embodiment of a filterelement;

FIG. 4B is a longitudinal section view of embodiment of FIG. 4A,including internal expanding elements having expanded to disrupt thefilter element and its overlying wrapping layers;

FIG. 5 is an exploded perspective view of a smoking article having theform of a cigarette, showing the smokable material, the wrappingmaterial components, and the filter element of the cigarette;

FIG. 5A shows one embodiment of a tipping material with holes;

FIG. 5B shows another embodiment of a tipping material with holes;

FIGS. 6A and 6B show, respectively, “before” and “after” images ofcigarettes exposed to water, including a control and two cigarettesembodying aspects of the present invention;

FIG. 7 shows a longitudinal section view of a cigarette, the filter ofwhich includes a capsule of a degradation-enhancing material;

FIG. 8 shows a longitudinal section view of a cigarette, the filter ofwhich includes an elongate pellet of a degradation-enhancing material;

FIG. 9 shows a longitudinal section view of a cigarette, the filter ofwhich includes a plurality of capsules;

FIG. 10 shows a longitudinal section view of a cigarette, the filter ofwhich includes a rod of a degradation-enhancing material; and

FIG. 11 shows a longitudinal section view of a cigarette, the filter ofwhich includes a plurality of threads of a degradation-enhancingmaterial.

DETAILED DESCRIPTION

Embodiments of the invention are described with reference to thedrawings in which like elements are generally referred to by likenumerals. The relationship and functioning of the various elements ofthis invention may be better understood by reference to the followingdetailed description. However, the embodiments of this invention are notlimited to the embodiments illustrated in the drawings. It should beunderstood that the drawings are not necessarily to scale, and incertain instances details may have been omitted which are not necessaryfor an understanding of the present invention, such as conventionalfabrication and assembly. As used in this specification and the claims,the singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise.

As shown in FIG. 1, a smoking article 100 may be embodied as acigarette. The cigarette 100 includes a generally cylindrical rod 102 ofa charge or roll of smokable filler material contained in acircumscribing wrapping material 106. The rod 102 is conventionallyreferred to as a “tobacco rod.” The ends of the tobacco rod 102 are opento expose the smokable filler material. The cigarette 100 is shown ashaving one optional band 122 (e.g., a printed coating including afilm-forming agent, such as starch, ethylcellulose, or sodium alginate)applied to the wrapping material 106, and that band circumscribes thecigarette rod in a direction transverse to the longitudinal axis of thecigarette. That is, the band 122 provides a cross-directional regionrelative to the longitudinal axis of the cigarette. The band 122 can beprinted on the inner surface of the wrapping material (i.e., facing thesmokable filler material), or less preferably, on the outer surface ofthe wrapping material. Although the cigarette can possess a wrappingmaterial having one optional band, the cigarette also can possesswrapping material having further optional spaced bands numbering two,three, or more.

A filter element 126 is disposed at the mouth end 120 of the tobacco rod102, and the lighting end 118 is positioned at the opposite end. Thefilter element 126 is axially aligned in an end-to-end relationship withand preferably abutting the tobacco rod 102. Filter element 126 may havea generally cylindrical shape, and its diameter may be substantially thesame as the diameter of the tobacco rod. The proximal and distal ends126 a, 126 b (respectively) of the filter element 126 preferably permitthe passage of air and smoke therethrough.

One exemplary filter element 126 configuration is shown in longitudinalsection in FIG. 2. The filter includes a first filter segment 232 thatis positioned immediately adjacent one end of the tobacco rod 102. Thefirst filter segment 232 includes filter material 240 (e.g., celluloseacetate tow impregnated with plasticizer, such as triacetin). Aplurality of degradation-enhancing objects (e.g., expandable members),here embodied as superabsorbent objects 250, is disposed within thefilter material 240 of the first segment. If desired, the filter elementmay also incorporate other components that have the ability to alter theproperties of the mainstream smoke that passes throughout the filterelement, such as adsorbent materials or flavorants. Exemplary adsorbentmaterials include activated carbon and ion exchange resins, andexemplary flavorants include flavorant-containing capsules and solidbotanical additives such as peppermint or spearmint leaves or otherplant-based flavorants in particulate form. See, for example, U.S. Pat.No. 6,041,790 to Smith et al. and U.S. Pat. Application Publication Nos.2004/0237984 to Figlar et al.; 2005/0268925 to Schluter et al.;2006/0130861 to Luan et al.; and 2006/0174899 to Luan et al., each ofwhich is incorporated herein by reference.

Exemplary superabsorbent materials included sodium (polyacrylate)polyacrylamide copolymer, ethylene maleic anhydride copolymer,cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymers,cross-linked polyethylene oxide, various hydrogels including so-called“hydrogel crystals,” and starch-grafted copolymer of polyacrylonitrile,or any other suitable superabsorbent polymer or non-polymeric material.Preferred superabsorbent materials will volumetrically expand uponcontact with material, such as—for example—water, that may commonly belocated in cigarette filter disposal locations. Volumetric expansion ofpreferred superabsorbent materials will preferably be by amultiplicative factor of at least two, but volumetric expansion ofpreferred materials may be about 6× to about 8× or greater. In a typicaldisposal situation where a filter is properly disposed of into areceptacle and makes its way into a landfill, contact with moisture suchas water or other materials in a typical waste-disposal site will allowand enable the volumetric expansion. Then, the volumetric expansion willdisrupt and spread apart the filter fibers, and will also break open theplug wrap 128 and tipping material 146, each of which is configured as apaper or paper-like material subject to ripping, tearing, bursting,and/or other disruption when subjected to mechanical force—particularlyin the presence of moisture. (see, e.g. FIG. 4B).

Other examples of materials useful to form or be included in (alone, orin combination with other materials) absorbent/expanding filter insertsinclude polyacrylate with poly(ethylene glycol), alginate-poly(sodiumacrylate-coacrylamide), alginate-g-poly(sodium acrylate)/kaolin,carboxymethylchitosan-g-poly(acrylic acid) copolymer, acrylic acid andmaleic anhydride-copolymerizate, polyvinylalcohol-phosphate, acrylicacid-polyvinyl alcohol copolymer, polyacrylamide,acrylamide/N-vinyl-pyrrolidone/3(2-hydroxyethyl carbamoyl)acrylic acid,poly(acrylamide-co-methyl methacrylate), polyacrylamide/sodium alginate,polyacrylic acid, poly(sodium acrylate) cross-linked with modifiedpoly(ethylene glycol), sulfonated polystyrene, hydrolysed acrylonitrilesulfonated polystyrene, poly(ethylene oxide), n-vinyl-2-pyrrolidone andpartially neutralized acrylic acid, poly(tartaramide)s,poly(ester-amide)s containing oxyethylene segments, poly(aspartic acid)and its derivatives, and/or poly(acrylic acid)/attapulgite/sodiumhumate.

All of these disruptive actions combine to allow for easier dispersaland degradation of the filter material. Certain microbes, includingvarious bacteria and fungi are known to degrade superabsorbent polymers,which—when provided in certain embodiments—may also assist in thedegradation of a disposed filter. For example, certain strains of thefungus Trichoderma reesei have the ability to secrete large quantitiesof cellulotic (e.g., cellulase and hemicellulase) enzymes. Somecellulase enzymes may break down cellulose components into water-solublesugars including, for example, glucose. As another example, the whiterot fungus Phanerochaete chrysosporium is known to biodegradepolyacrylates and polyacrylate/polyacryalamide copolymers. (see, e.g.,

Biodegradation of Superabsorbent polymers in soil, James Stahl et al,Environ. Sci. & Pollut., Research 7(2) 83-88 (2000)). As anotherexample, starch-grafted-polyacrylonitrile superabsorbent polymers havebeen shown to be biodegraded by naturally occurring, gram-positivecocco-bacillary rod shaped bacterial cultures (see, e.g., Microbialdegradation of Superabsorbent HSPAN Gel by an Indigenously IsolatedBacterial Culture, Gosavi et al, Macromolecules, 1999, 32 (13) PP4264-4271). One or more of these may be provided.

Although it is not desirable or preferred, some cigarette filters aredisposed of by being flushed into water disposal lines or by being leftin an open/exposed environment. In these and other disposalcircumstances, the volumetric expansion facilitated in embodimentsdescribed herein will also hasten the degradation of disposed filters bydisrupting the filter and thereby increasing the access ofdegradation-enhancing environmental components to the filter elements.

The term “degradation-enhancing object” should be understood within thepresent specification to refer to discrete objects disposed upon and/orwithin fibrous filter tow material. These discrete objects will expandupon contact with moisture in a disposal environment, and/or that willactively disperse and/or degrade fibrous filter tow material and thatmay also actively disperse and/or degrade material such as plug wrap ortipping paper around the filter tow. As such, the term excludesmaterials such as starches that are taught as being themselvesdegradable for enhancing filter degradation without the expansioncharacteristics of the presently-disclosed materials.

The filter 126 may include a second filter segment 236 longitudinallydisposed relative to the first segment 232 and positioned at the mouthend 120 of the cigarette 100. The second filter segment 236 includesfilter material 248 (e.g., cellulose acetate tow impregnated withplasticizer, such as triacetin). In the embodiment shown in FIG. 2, thesecond filter segment 236 does not include the superabsorbent objects250; however, such objects can be present in and/or on all filtersegments, if desired. A filter segment may be considered devoid of thesuperabsorbent objects when it includes no more than about 0.5 weightpercent of the superabsorbent objects, based on the total weight of thefilter segment.

The filter element 126 is circumscribed along its outer circumferentialsurface and/or or longitudinal periphery by a layer of outer plug wrap128. In the embodiment of FIG. 2, outer plug wrap 128 overlies each ofthe first filter segment 232 and the second filter segment 236, so as toprovide a combined, two-segment filter element. However, it should beappreciated that a single-segment filter element and/or multi-segmentfilter elements having two or more segments (one or more of whichincludes at least one superabsorbent objects) may also be made and usedwithin the scope of the present invention.

The filter element 126 is attached to the tobacco rod 102 using tippingmaterial 146 (e.g., essentially air impermeable tipping paper), thatcircumscribes both the entire length of the filter element 126 and anadjacent region of the tobacco rod 102. In certain preferredembodiments, the inner surface of the tipping material 146 may befixedly secured to the outer surface of the plug wrap 128 and the outersurface of the wrapping material 106 of the tobacco rod using a suitableadhesive, which attaches the filter element and the tobacco rod to oneanother.

A ventilated or air diluted smoking article can be provided with anoptional air dilution means, such as a series of perforations 130, eachof which extend through the tipping material and plug wrap. The optionalperforations 130, shown in FIG. 1, may be made by various techniquesknown to those of ordinary skill in the art, such as laser perforationtechniques. Alternatively, so-called off-line air dilution techniquescan be used (e.g., through the use of porous paper plug wrap andpre-perforated tipping paper). For cigarettes that are air diluted orventilated, the amount or degree of air dilution or ventilation canvary. Frequently, the amount of air dilution for an air dilutedcigarette may be greater than about 10 percent, generally may be greaterthan about 20 percent, and sometimes is greater than about 40 percent.The upper level for air dilution for an air diluted cigarette may beless than about 80 percent, and often is less than about 70 percent. Asused herein, the term “air dilution” is the ratio (expressed as apercentage) of the volume of air drawn through the air dilution means tothe total volume and air and smoke drawn through the cigarette andexiting the extreme mouth end portion of the cigarette.

During use, the smoker typically lights the lighting end 118 of thecigarette 100 using a match or cigarette lighter, whereupon the smokablematerial 102 begins to burn. The mouth end 120 of the cigarette 100 isplaced in the lips of the smoker. Thermal decomposition products (e.g.,components of tobacco smoke) generated by the burning smokable material102 are drawn through the cigarette 100, through the filter element 126,and into the mouth of the smoker. Following use of the cigarette 100,the filter element 126 and any residual portion of the tobacco rod 102may be discarded.

As described above, the presence of the superabsorbent objects canincrease the rate of degradation of the filter element 126. Expansion ofthe superabsorbent objects through and pushing against the surroundingfibrous tow material, plug wrap, and tipping paper/material will disruptthe tight, typically water-resistant construction of the filter element126, allowing spaces/voids between those components. The voids provideadditional surface area within the filter element 126 for contact withenvironmental elements such as moisture and air, which may enhance therate of degradation of the filter.

Other filter element arrangements may be used without departing from theinvention. For example, the filter element could include more than thetwo segments set forth in FIG. 2. The filter element could also includea cavity formed between two filter material segments. Still further, thefilter segment comprising the dispersed superabsorbent objects and/orother degradation-enhancing object(s) can be more centrally locatedwithin the filter element with one or more filter segments that do notcontain the particles on each side. Alternatively, all filter segmentscould include the superabsorbent objects.

Another embodiment is shown in FIG. 3, which illustrates a three-segmentfilter 326. As shown in FIG. 3, a first filter segment 331 is disposedimmediately adjacent the tobacco rod 102 and held thereto by plug wrap128 and tipping material 146. The first segment 331 includessuperabsorbent objects 350 disposed at the interface between the plugwrap 128 and the filter material 240, and preferably configured, likethe other objects described herein, to exert sufficient mechanical forcewhen in contact with moisture in a disposal environment to disrupt theplug wrap and/or tipping material, as well as spreading apart the fibersof fibrous filter tow. A second filter segment 332 is disposedimmediately adjacent the first segment 331, nearer the mouth end. Itincludes a plurality of superabsorbent objects embodied as crystalshaped particles 351 dispersed through the filter material 240.

FIGS. 4A and 4B depict a two-segment filter 426. As shown in FIG. 4A, afirst filter segment 432 is disposed immediately adjacent the tobaccorod 102 and held thereto by plug wrap 128 and tipping material 146. Thefirst segment 432 includes a superabsorbent object 450 embodied as afirst capsule 450. A second filter segment 436 is disposed adjacent andslightly spaced apart from the first segment 432, nearer the mouth end.It includes a superabsorbent object 454 embodied as a second capsule 454incorporated into the filter material 240. FIG. 4B shows the filter 426after it has been exposed to moisture or another instrumentalityactivating the superabsorbent objects 450, 454. Those objects havevolumetrically expanded, forcing rupturing of the plug wrap 128 and thetipping material 146. In addition, this volumetric expansion will haveloosened the fibers of the filter material 240, allowing them to be moreeasily dispersed and degraded. In these and/or other embodiments, adegradation-enhancing object such as superabsorbent object 454 may alsobe disposed in a space between filter segments.

Certain embodiments may include perforation through the tipping materialand/or plug wrap of a cigarette, as is described with reference to FIG.5, which shows an exploded view of a cigarette 500. A cigaretteembodiment 500 may be constructed including a tobacco rod 502,circumscribed by a wrapping material 506. A filter 126 made of acetatetow or other filter material providing for longitudinal passage of airtherethrough may be circumscribed by plug wrap (not shown separately),which may in turn be circumscribed by tipping material 546, configuredto attach the filter portion to the tobacco rod portion of the cigarette500. As described above, the plug wrap and/or tipping material 546 mayinclude a circumferential or other pattern (or non-pattern) ofperforations 530 formed mechanically, by laser (which is generallypreferred), or by some other means. In the cigarette embodiment 500, agenerally longitudinal plurality of perforations 533 is also provided.(The perforations are shown as rather large, but—as noted above—are notnecessarily drawn to scale, and may be different in both relative andabsolute size, geometry, and dimensions).

The generally longitudinal plurality of perforations 533 may be formedsubstantially co-linear with the central longitudinal axis of thecigarette 500 as shown. However, the generally longitudinal plurality ofperforations 533 may be formed in a wavy pattern (FIG. 5A), helicalpattern (FIG. 5B), or in any other generally longitudinal orientationthat extends from at or near a distal/ lighting end of the filterportion to, or at least near to the mouth-end of the filter portion. Instill other embodiments, the perforations 533 may be formed into apattern such as, for example, lettering, logo(s), geometric patterns, orother designs. The perforations preferably are disposed so as to allowmaterials overlying the filter material (e.g., plug wrap, tippingmaterial) more easily to split or otherwise be disrupted when subjectedto mechanical forces from an expanding object in the filter. Filtermaterials such acetate tow commonly exhibit a generally longitudinalorientation or grain, the end(s) of which are exposed at the generallycylindrical end(s) of the filter. As a result, moisture entering theexposed end(s) tends to travel longitudinally through the filter.

Then, when one or more expandable objects such as fibrous materials,inserted objects, or other materials placed in or on the filter (suchas—for example—those items discussed elsewhere in this specification)expand, the mechanical forces of that expansion are directed toward thecircumference of the filter material 526, such that at least a portionof the mechanical force (generated by the expansion of the object(s)) isgenerally transverse to the wrapping material 546 and (if present) plugwrap, as well as generally transverse to the longitudinal orientation orgrain of the filter materials. In each of the embodiments describedherein, the expansive forces of the object(s) in the presence ofmoisture will promote rupture of the wrapper (e.g., plug wrap, tippingmaterial) constraining the filter material and/or will promoteseparation of the fibrous and other materials forming the filter,thereby promotion dispersion and degradation of the filter. The presenceof moisture will also promote weakening of the wrapping around thefilter (e.g., plug wrap, tipping material), which may be aided by theconstruction of the filter wrapping as in the perforated embodiments ofFIGS. 5-5B and/or by the composition of the filter wrapping (e.g.,providing filter wrapping that provides desirable qualities for theforces and level of moisture encountered during manufacture, storage,and use of cigarettes, while allowing permeation and weakening and/ordegradation in the presence of moisture encountered in a disposalenvironment).

The generally longitudinal plurality of perforations 533 provides a“tearable portion” of the filter region. When an expandable material inthe filter is activated and exerts radial force within and/or againstthe filter material 526 against the plug wrap and tipping material 546,the generally longitudinal plurality of perforations 533 preferably isconfigured such that swelling or other volumetric expansion of an innermember of the filter 526 will tear the plug wrap and tipping material546 therealong. In this and all embodiments including an expandablemember in and/or on the filter material, it is most preferable thatmoisture conditions encountered during normal use will not activate theexpandable member sufficiently to adversely affect functionality of thefilter with regard to air flow, flavor transmission, and integrity ofthe filter material and surrounding plug wrap and/or tipping material.

In addition to the superabsorbent objects described above, somecigarette embodiments may include one or more pellets, particles,threads, rods, and/or other-shaped units of a cellulosic polymer thatswells when exposed to moisture. The degree of swelling/expansionoccasioned by smoking a cigarette so embodied (e.g., from the mouth ofthe smoker, from moisture/heat generated by pyrolysis of the tobaccorod) preferably will not occur during the consumption of the cigarettein a manner that would adversely affect functionality of the filter withregard to air flow, flavor transmission, and integrity of the filtermaterial and surrounding plug wrap and/or tipping material. Cigarettesaccording to such an embodiment may be constructed in any manner asdescribed above with reference to one or more of FIGS. 2 through 5B, orany other manner appropriate to provide expansion and disruption of thefilter material. In addition, these and other embodiments of a cigarettemay include an adhesive used to adhere one or more of wrapping material,tipping material, and plug wrap to each other and/or themselves, wherethe adhesive is configured to release (e.g., by degradation or othermechanism) when exposed to a high level of moisture.

During manufacture of typical cigarette filters, two types of adhesivesare commonly used: (1) a hot melt adhesive for gluing the edges of theplug wrap, and (2) an aqueous dispersion based adhesive for gluing thetipping paper. Although the physical form of these adhesives may bedifferent, both types typically include ethylene vinyl acetate as themain polymeric ingredient. Ethylene vinyl acetate is not generallyconsidered a readily biodegradable polymer. In formulating cigarettefilters for accelerated degradability (e.g., by employing structuresdisclosed herein, or forming a filter from polymers that havedemonstrated accelerated biodegradability), it may be desirable that theadhesive that holds the fibers together within the two layers of paperare also biodegradable. Certain biodegradable adhesives may be used incigarette filters as hot melts and as aqueous dispersions.

Commercially available biodegradable polymers that can be used directlyas hot melts or used after blending with commonly used plasticizers andtackifiers include, for example, thermoplastic starches (e.g., Biogradepolymers from Biograde Ltd., Biolice polymer from Limgrane, Biomax fromDuPont, Bioplast from Biotec, Cereloy Bio polymer from Cerestech Inc.,Getrex polymer from IGV, Grace Bio GB 100 polymer from Grace Biotech,Mater-Bi polymers from Novamont, Plantic polymers from Plantic, Re-Newpolymers from Starch Tech, Solanyl BP from Rodenburg Biopolymers); lendsof thermoplastic starches and polyolefins (e.g., BioCeres polymers fromFuturaMat, Biograde polymers from Biograde Ltd., Cereloy Eco fromCerestech Inc., CP-Bio PP from Cereplast); blends of thermoplasticstarches and polyvinyl alcohol (e.g., Biograde WS from Biograde); blendsof thermoplastic starches and biodegradable aliphatic polyesters (e.g.,Biopar polymers from BiOP Polymer Technologies, Bioplast polymers fromBiotec); and/or blends of thermoplastic starch and polylactic acid(e.g., CP-EXC, CP-INJ, and CP-TH series from Cereplast). Biodegradablepolymers that may be applied as aqueous dispersions can be used astipping glue after converting them to dispersions by one or more ofseveral methods.

With a solvent-antisolvent approach, the polymer is first dissolved in awater miscible organic solvent. The precipitation of the polymer intodispersion is induced by mixing the solution with water. Anotherapproach includes evaporative precipitation in to a dispersion, wherethe polymer is dissolved in an organic solvent which is not misciblewith water, and the polymer solution is then sprayed into heated waterresulting in an immediate evaporation of the organic solvent, whichimmediately forms the polymer particles are formed into a dispersion.During a wet ball milling process, micronized powder of the polymer ischarged in to ball mill containing milling media (e.g., zirconiumdioxide beads, silicium nitride beads, polystyrene beads) with anaqueous stabilizer, which is typically a surfactant. The moving millingmedia generates high shear forces and causes attrition of the originalpolymer particles to form a dispersion. High pressure homogenization isa process performed at room temperature with a piston gap homogenizer inan aqueous medium. During this process, a coarse suspension is formedthrough a very tiny homogenization gap. The particle size reduction to adispersion is caused by cavitation forces, shear forces, and particlecollision. During a microfluidics particle size reduction method, thepolymeric material is subjected to ultra high shear forces to break downto smaller sizes that can be dispersed in water and stabilized with asurfactant. Another method uses supercritical fluid technology where asupercritical fluid such as CO2 is used to effect a particle sizereduction of the starting polymer that can then be dispersed intoaqueous media. During a spray drying process, the polymer is first spraydried to obtain a powder and then dispersed and stabilized in water witha surfactant. These or other methods may be used to apply one or more ofthe biodegradable adhesives noted herein, or other adhesive(s) to securetipping paper and/or plug wrap. The tipping paper and/or plug wrap thussecured will be more easily released to expose underlying filtermaterials to biodegradation or other degradation processes.

In addition to the filter-disrupting elements described herein, someembodiments may include other degradability/ biodegradability featuressuch as disposition of one or more non-hazardous agents, distinct fromthe degradation-enhancing objects of the present specification. Theseother features (e.g., microbial agents, cellulase and/or other enzymaticagents) may be selected for being non-hazardous and for being able tolie dormant during normal storage, transport, and—optionally—smokingconditions, then activated to propagate and consume one or more of thematerials forming the cigarette (e.g., filter tow, other filtermaterial, plug wrap, tipping material, wrapping material) when exposedto moisture.

FIGS. 6A-6B illustrate a comparative example using a standard cigarette680 (a Camel® Wide), a first capsule-containing cigarette embodiment660, and a second capsule-containing cigarette embodiment 670 (alsoCamel® Wide cigarettes). The cigarettes are substantially alike in allaspects, except that the first and second capsule-containing embodiments660, 670 each have a superabsorbent capsule 665 (not visible in FIG. 6A)inserted into the filter tow 692 making up the filter, with care havingbeen exercised not to disrupt the tipping material 693 encircling thefilter tow 692. (It is expected that—in longitudinal section—thesecigarettes, before smoking, would appear substantially similar to thoseshown in FIG. 7). The capsule used was a commercially availablewater-storing gel bead (JRM Chemical, Inc. of Cleveland, Ohio). Allthree cigarettes 660, 670, 680 were smoked under the same standardconditions for about the same amount of time. Then they weresubstantially simultaneously placed into a container 695 of water. Afterabout 10 minutes, as shown in FIG. 6A, one of the capsule-containingembodiments 670 already showed signs of the tipping paper 693 startingto open along its seam 694, but the “control cigarette” 680 shows nosign of change.

After about 30 minutes, as shown in FIG. 6B (where the cigarettes arerotated to more clearly show the effect), the tipping paper 693 of eachof the capsule-containing embodiments 660, 670 is substantially openalong its seam, but the “control cigarette” 680 still shows no sign ofchange along its seam. After this time, the standard cigarette 680 wassubstantially unaffected other than having gotten wet, while thesuperabsorbent capsule 665 of the first and second capsule-containingembodiments 660, 670 have volumetrically expanded so much that they havesplit open the tipping paper seams 694 and started spreading out thefilter tow 692. As shown in FIG. 6B, the wrapping material overlying thefilter tow 692 of both of the capsule-containing cigarettes 660, 670 wasdisrupted from within by the mechanical forces exerted by volumetricexpansion of the capsule therein. As a result, the filter tow is alreadybeing spread apart such that it may more readily be dispersed and/ordegraded. Over a longer time, the expansion will increase, and—in manydisposal environments—the filter tow of cigarettes equipped with such avolumetrically-expanding degradation-enhancing element will disperse ina far more rapid time than would the filter material of the standardcigarette.

The splitting at seam 694 in this and other embodiments may be enhancedby use of a water-soluble (or at least water-sensitive orwater-degradable) adhesive along the plug wrap seam 694. Examples ofappropriate adhesives include those described in U.S. Pat. Nos.5,453,144 and 5,498,224 to Kauffman et al. and U.S. Pat. No. 5,709,227to Arzonico et al., each of which is incorporated by reference herein.

FIG. 7 shows a cigarette 710 including a one-segment filter 726. Thematerial 740 (e.g., acetate tow or other appropriate material) making upthe filter 726 surrounds a capsule 750 of a degradation-enhancingmaterial such as, for example, a compound configured to volumetricallyexpand upon contacting moisture. The filter material 740 may beencompassed by plug wrap 728 and tipping material 746, and be attachedto a wrapping material-encompassed tobacco rod 702.

FIG. 8 shows a cigarette 810 including a one-segment filter 826. Thematerial 840 (e.g., acetate tow or other appropriate material) making upthe filter 826 surrounds an elongate pellet 850 of adegradation-enhancing material such as, for example, a compoundconfigured to volumetrically expand upon contacting moisture. The filtermaterial 840 may be encompassed by plug wrap 828 and tipping material846, and be attached to a wrapping material-encompassed tobacco rod 802.

FIG. 9 shows a cigarette 910 including a one-segment filter 926. Thematerial 940 (e.g., acetate tow or other appropriate material) making upthe filter 926 surrounds a trio of capsules 950 of adegradation-enhancing material such as, for example, a compoundconfigured to volumetrically expand upon contacting moisture. The filtermaterial 940 may be encompassed by plug wrap 928 and tipping material946, and be attached to a wrapping material-encompassed tobacco rod 902.

FIG. 10 shows a cigarette 1010 including a one-segment filter 1026. Thematerial 1040 (e.g., acetate tow or other appropriate material) makingup the filter 1026 generally encircles a rod 1050 of adegradation-enhancing material such as, for example, a compoundconfigured to volumetrically expand upon contacting moisture. The filtermaterial 1040 may be encompassed by plug wrap 1028 and tipping material1046, and be attached to a wrapping material-encompassed tobacco rod1002.

FIG. 11 shows a three-segment filter 1126 of a cigarette. The material1140 (e.g., acetate tow or other appropriate material) making up thecentral segment of the filter 1126 surrounds a plurality of threads 1150of a degradation-enhancing material such as, for example, a compoundconfigured to volumetrically expand upon contacting moisture and/oranother material as described herein. The filter material 1140 may beencompassed by plug wrap 1128 and tipping material 1146, and be attachedto a wrapping material-encompassed tobacco rod.

Each of the embodiments included herein may include a coating around theexpandable/ expanding objects and/or degradability-enhancing features,where the coating is configured to protect the coated feature frommoisture for a certain amount of time and/or moisture-volume exposure.Moisture-soluble and moisture disruptable coatings are well-known in theconfectionary and pharmaceutical arts. As one example, a thin gelatincoating may be used to coat the expandable and/or otherdegradation-enhancing features in a cigarette filter, where the thingelatin coating will generally withstand moisture levels associated withtypical transport, storage, and use of a cigarette without adverselyaffecting the cigarette, but will be dissolved or otherwise disruptedupon contact with a level of moisture encountered in a disposalenvironment thereby exposing the coated feature and allowing itsactivation.

The dimensions of a representative cigarette 100 may vary. Preferredcigarettes are rod-shaped, and can have diameters of about 7.5 mm (e.g.,circumferences of about 20 mm to about 27 mm, often about 22.5 mm toabout 25 mm); and can have total lengths of about 70 mm to about 120 mm,often about 80 mm to about 100 mm. The length of the filter element 30can vary. Typical filter elements can have total lengths of about 15 mmto about 40 mm, often about 20 mm to about 35 mm. For a typicaldual-segment filter element, the downstream or mouth end filter segmentoften has a length of about 10 mm to about 20 mm; and the upstream ortobacco rod end filter segment often has a length of about 10 mm toabout 20 mm.

Various types of cigarette components, including tobacco types, tobaccoblends, top dressing and casing materials, blend packing densities andtypes of paper wrapping materials for tobacco rods, can be employed.See, for example, the various representative types of cigarettecomponents, as well as the various cigarette designs, formats,configurations and characteristics, that are set forth in Johnson,Development of Cigarette Components to Meet Industry Needs, 52ndT.S.R.C. (September, 1998); U.S. Pat. No. 5,101,839 to Jakob et al.;U.S. Pat. No. 5,159,944 to Arzonico et al.; U.S. Pat. No. 5,220,930 toGentry and U.S. Pat. No. 6,779,530 to Kraker; U.S. Pat. Publication Nos.2005/0016556 to Ashcraft et al.; 2005/0066986 to Nestor et al.;2005/0076929 to Fitzgerald et al.; 2006/0272655 to Thomas et al.;2007/0056600 to Coleman, III et al.; and 2007/0246055 to Oglesby, eachof which is incorporated herein by reference. Most preferably, theentire smokable rod is composed of smokable material (e.g., tobacco cutfiller) and a layer of circumscribing outer wrapping material.

The filter material can vary, and can be any material of the type thatcan be employed for providing a tobacco smoke filter for cigarettes.Preferably a traditional cigarette filter material is used, such ascellulose acetate tow, gathered cellulose acetate web, polypropylenetow, gathered cellulose acetate web, gathered paper, strands ofreconstituted tobacco, or the like. This may include gathered webfilters using paper and/or one or more non-woven fabrics. Especiallypreferred is filamentary or fibrous tow such as cellulose acetate,polyolefins such as polypropylene, or the like. One filter material thatcan provide a suitable filter rod is cellulose acetate tow having 3denier per filament and 40,000 total denier. As another example,cellulose acetate tow having 3 denier per filament and 35,000 totaldenier can provide a suitable filter rod. As another example, celluloseacetate tow having 8 denier per filament and 40,000 total denier canprovide a suitable filter rod. For further examples, see the types offilter materials set forth in U.S. Pat. No. 3,424,172 to Neurath; U.S.Pat. No. 4,811,745 to Cohen et al.; U.S. Pat. No. 4,925,602 to Hill etal.; U.S. Pat. No. 5,225,277 to Takegawa et al. and U.S. Pat. No.5,271,419 to Arzonico et al.; each of which is incorporated herein byreference.

Normally a plasticizer such as triacetin or carbowax is applied to thefilamentary tow in traditional amounts using known techniques. In oneembodiment, the plasticizer component of the filter material comprisestriacetin and carbowax in a 1:1 ratio by weight. The total amount ofplasticizer is generally about 4 to about 20 percent by weight,preferably about 6 to about 12 percent by weight. Other suitablematerials or additives used in connection with the construction of thefilter element will be readily apparent to those skilled in the art ofcigarette filter design and manufacture. See, for example, U.S. Pat. No.5,387,285 to Rivers, which is incorporated herein by reference.

Filamentary tow, such as cellulose acetate, is processed using aconventional filter tow processing unit such as a commercially availableE-60 supplied by Arjay Equipment Corp., Winston-Salem, N.C. Other typesof commercially available tow processing equipment, as are known tothose of ordinary skill in the art, may similarly be used.

As illustrated in FIG. 2 and some other figures, the filter elementsdisclosed herein may include a plurality of longitudinally-extendingsegments. Each segment can have varying properties and may includevarious materials capable of filtration or adsorption of particulatematter and/or vapor phase compounds. Typically, a filter element of theinvention will include 1 to 6 segments, and frequently may include 2 to4 segments. In preferred embodiments, the degradation-enhancing objectssuch as, for example—superabsorbent objects, will not be disposed in thetobacco rod.

In addition to degradation-enhancing objects (e.g., superabsorbentobjects) the filter may include materials constructed to speed orotherwise facilitate breakdown of the filter. These materials (which aredistinct from the degradation-enhancing objects) can be made of anyfiller material that is itself degradable, meaning the material iscapable of undergoing degradation or decomposition, for example throughchemical reaction that breaks down the particles into decompositionproducts, particularly under environmental conditions associated withdisposal of the filter material. One exemplary type of degradation isbiodegradation. As used herein, the term “biodegradable particle” refersto a particulate material that degrades under aerobic and/or anaerobicconditions in the presence of bacteria, fungi, algae, and othermicroorganisms to carbon dioxide/methane, water and biomass, althoughmaterials containing heteroatoms can also yield other products such asammonia or sulfur dioxide. “Biomass” generally refers to the portion ofthe metabolized materials incorporated into the cellular structure ofthe organisms present or converted to humus fractions indistinguishablefrom material of biological origin.

Biodegradability can be measured, for example, by placing a sample inenvironmental conditions expected to lead to decomposition, such asplacing a sample in water, a microbe-containing solution, a compostmaterial, or soil. The degree of degradation can be characterized byweight loss of the sample over a given period of exposure to theenvironmental conditions. Exemplary rates of degradation for certainfilter element embodiments of the invention include a weight loss of atleast about 20% after burial in soil for 60 days or a weight loss of atleast about 30% after 15 days of exposure to a typical municipalcomposter. However, rates of biodegradation can vary widely depending onthe type of degradable particles used, the remaining composition of thefilter element, and the environmental conditions associated with thedegradation test. U.S. Pat. No. 5,970,988 to Buchanan et al. and U.S.Pat. No. 6,571,802 to Yamashita provide exemplary test conditions fordegradation testing.

Exemplary biodegradable materials include, without limitation, starch,cellulosic or other organic plant-derived fibrous materials (e.g.,cotton, wool, cedar, hemp, bamboo, kapok, or flax), polyvinyl alcohol,aliphatic polyesters, aliphatic polyurethanes, cis-polyisoprene,cis-polybutadiene, polyhydroxy alkanoates, polyanhydrides, andcopolymers and blends thereof. The term “aliphatic polyester” refers topolymers having the structure —[C(O)—R—O]_(n)—, wherein n is an integerrepresenting the number of monomer units in the polymer chain and R isan aliphatic hydrocarbon, preferably a C1-C10 alkylene, more preferablya C1-C6 alkylene (e.g., methylene, ethylene, propylene, isopropylene,butylene, isobutylene, and the like), wherein the alkylene group can bea straight chain or branched. Exemplary aliphatic polyesters includepolyglycolic acid (PGA), polylactic acid (PLA) (e.g., poly(L-lacticacid) or poly(DL-lactic acid)), polyhydroxy butyrate (PHB), polyhydroxyvalerate (PHV), polycaprolactone (PCL), and copolymers thereof. Thesedegradable (including biodegradable) materials may include, for example,any of the materials described in pending U.S. patent application Ser.No. 12/539,226, which is incorporated herein by reference.

The particle size of the degradable particles (e.g., starch particles)can vary, but is typically small enough to ensure uniform dispersionthroughout the fibrous tow filter material without unduly affecting thedesirable filtration and mechanical properties of the fibrous tow. Asused herein, reference to “particles” or “particulate” materials simplyrefers to discrete units of relatively small size but does not restrictthe cross-sectional shape or overall geometry of the material, which canbe characterized as spherical, oblong, ovoid, flake-like, irregular orthe like without departing from the invention. The degradable particlesusually have a particle size range of about 100 nm to about 20 microns,more typically about 400 nm to about 800 nm, and most often about 400 nmto about 600 nm. In certain embodiments, the particle size of thedegradable particles can be characterized as less than about 20 microns,less than about 800 nm, or less than about 600 nm. Certain embodimentsof the degradable particles can be characterized as having a particlesize of more than about 100 nm or more than about 400 nm.

The amount of degradable particles used in a filter element can vary,but typical weight percentages are in the range of about 5 to about 30%by weight, based on the overall dry weight of the filter element, moretypically about 10 to about 20% by weight. In certain embodiments, theamount of degradable particles in the filter element can becharacterized as more than about 5% by weight, more than about 10% byweight, or more than about 15% by weight, but less than about 60% byweight, less than about 50% by weight, or less than about 40% by weight.

In certain embodiments, the degradable particles (e.g., starchparticles) are characterized as having certain solubility properties.For example, in certain applications, it may be desirable for theparticles to have a high degree of solubility in water. In otherembodiments, hydrophobicity (i.e., relatively low water solubility) willbe desired. Many polymer materials, including starch materials, can bechemically modified in order to increase or reduce water solubility. Insome embodiments, the particles can be viewed as highly soluble inwater. In other embodiments, the particles have a low level ofsolubility in water and/or in certain other solvents, such as solventsused in the cellulose acetate fiber manufacturing process (e.g., theparticles can be insoluble in acetone). As used herein, the term“soluble” refers to a material with a solubility in the given solvent ofat least about 50 g/L, typically at least about 75 g/L, and often atleast about 100 g/L at 25° C. A material characterized as “insoluble”refers to a material having a solubility in the given solvent of no morethan about 5 g/L, typically less than about 2 g/L, and often less thanabout 0.5 g/L at 25° C.

The process for making filter elements according to the invention canvary, but a process for making cellulose acetate filter elementstypically begins with forming cellulose fibers. The first step inconventional cellulose acetate fiber formation is esterifying acellulose material. Cellulose is a polymer formed of repeating units ofanhydroglucose. Each monomer unit has three hydroxyl groups availablefor ester substitution (e.g., acetate substitution). Cellulose estersmay be formed by reacting cellulose with an acid anhydride. To makecellulose acetate, the acid anhydride is acetic anhydride. Cellulosepulp from wood or cotton fibers is typically mixed with acetic anhydrideand acetic acid in the presence of an acid catalyst such as sulfuricacid. The esterification process of cellulose will often result inessentially complete conversion of the available hydroxyl groups toester groups (e.g., an average of about 2.9 ester groups peranhydroglucose unit). Following esterification, the polymer is typicallyhydrolyzed to drop the degree of substitution (DS) to about 2 to about2.5 ester groups per anhydroglucose unit. The resulting product istypically produced in flake form that can be used in subsequentprocessing.

To form a fibrous material, the cellulose acetate flake is typicallydissolved in a solvent (e.g., acetone, methanol, methylene chloride, ormixtures thereof) to form a viscous solution. The concentration ofcellulose acetate in the solution is typically about 15 to about 35percent by weight. Additives such as whitening agents (e.g., titaniumdioxide) can be added to the solution if desired. The resulting liquidis sometimes referred to as a liquid “dope.”

The cellulose acetate dope is spun into filaments using a nonwovenfabric melt-spinning technique. The cellulose acetate dope is spun intofilaments by extruding the liquid dope through a spinneret. Thefilaments pass through a curing/drying chamber, which solidifies thefilaments prior to collection. The collected fibers are combined into atow band, crimped, and dried. Conventional crimp ratios are in the rangeof 1.2 to 1.8. The fibers are typically packaged in bales that aresuitable for later use in filter element formation processes.

The process of forming the actual filter element typically involvesmechanically withdrawing the cellulose acetate tow from the bale andseparating the fibers into a ribbon-like band. The tow band is subjectedto a “blooming” process wherein the tow band is separated intoindividual fibers. Blooming can be accomplished, for example, byapplying different tensions to adjacent sections of the tow band orapplying pneumatic pressure. The bloomed tow band then passes through arelaxation zone that allows the fibers to contract, followed by passageinto a bonding station. The bonding station typically applies aplasticizer such as triacetin to the bloomed fibers, which softens thefibers and allows adjacent fibers to fuse together. The bonding processforms a homogenous mass of fibers with increased rigidity. The bondedtow is then wrapped in plug wrap and cut into filter rods. Celluloseacetate tow processes are set forth, for example, in U.S. Pat. No.2,953,838 to Crawford et al. and U.S. Pat. No. 2,794,239 to Crawford etal., which are incorporated by reference herein.

For filter elements including an expandable or otherdegradation-enhancing objects embodied as one or more capsules orpellets, the filter-forming step may include placement of the one ormore capsules and/or pellets into assembled filter tow in a mannersimilar to methods now known and used for capsule or pellet insertion.Methods and machines for completing this assembly step include thosedisclosed in U.S. Pat. No. 7,115,085 to Deal et al. and U.S. Pat. No.7,479,098 to Thomas et al., each of which is incorporated by reference.Superabsorbent, otherwise expandable, and/or other degradation-enhancingobjects may be distributed into filter tow before or during the time itis spread and gathered for bulking, fed into the filter tow as it isgathered for bulking, placed into a cavity in the filter (e.g., in themanner used for providing charcoal granules in charcoal segmentedfilters), or by any other method appropriate for distributing one ormore particles, pellets, rods, threads, or other shaped or amorphousdegradation-enhancing objects including superabsorbent and otherexpandable objects. Methods for including a superabsorbent material intoa smoking article filter may include but are not limited to: capsuleinsertion technology, pellet insertion technology, thread insertiontechnology using a hydrogel or other superabsorbent polymer or othermaterial formed into a thread/strand or by adhering grains of hydrogelto a carrier thread, sprinkling of grains into tow band, and/orinclusion into filter tow with a plasticizer

Filter element components or segments for filter elements formulti-segment filtered cigarettes typically are provided from filterrods that are produced using traditional types of rod-forming units,such as those available as KDF-2 and KDF-3E from Hauni-Werke Korber &Co. KG. Typically, filter material, such as filter tow, is providedusing a tow processing unit. An exemplary tow processing unit has beencommercially available as E-60 supplied by Arjay Equipment Corp.,Winston-Salem, NC. Other exemplary tow processing units have beencommercially available as AF-2, AF-3, and AF-4 from Hauni-Werke Korber &Co. KG. In addition, representative manners and methods for operating afilter material supply units and filter-making units are set forth inU.S. Pat. No. 4,281,671 to Byrne; U.S. Pat. No. 4,862,905 to Green, Jr.et al.; U.S. Pat. No. 5,060,664 to Siems et al.; U.S. Pat. No. 5,387,285to Rivers; and U.S. Pat. No. 7,074,170 to Lanier, Jr. et al. Other typesof technologies for supplying filter materials to a filter rod-formingunit are set forth in U.S. Pat. No. 4,807,809 to Pryor et al. and U.S.Pat. No. 5,025,814 to Raker; which are incorporated herein by reference.

Cigarette filter rods can be used to provide multi-segment filter rods.The production of multi-segment filter rods can be carried out using thetypes of rod-forming units that traditionally have been employed toprovide multi-segment cigarette filter components. Multi-segmentcigarette filter rods can be manufactured using a cigarette filter rodmaking device available under the brand name Mulfi from Hauni-WerkeKorber & Co. KG of Hamburg, Germany. Representative types of filterdesigns and components, including representative types of segmentedcigarette filters, are set forth in U.S. Pat. No. 4,920,990 to Lawrenceet al.; U.S. Pat. No. 5,012,829 to Thesing et al.; U.S. Pat. No.5,025,814 to Raker; U.S. Pat. No. 5,074,320 to Jones, Jr. et al.; U.S.Pat. No. 5,105,838 to White et al.; U.S. Pat. No. 5,271,419 to Arzonicoet al.; U.S. Pat. No. 5,360,023 to Blakley et al.; U.S. Pat. No.5,396,909 to Gentry et al.; and U.S. Pat. No. 5,718,250 to Banerjee etal; U.S. Pat. Appl. Pub. Nos. 2002/0166563 to Jupe et al., 2004/0261807to Dube et al.; 2005/0066981 to Crooks et al.; 2006/0090769 to Woodsonet al.; 2006/0124142 to Zhang; 2006/0144412 to Mishra et al.,2006/0157070 to Belcastro et al.; and 2007/0056600 to Coleman, III etal.; PCT Publication No. WO 03/009711 to Kim; PCT Publication No. WO03/047836 to Xue et al.; all of which are incorporated herein byreference.

Multi-segment filter elements typically are provided from so-called“six-up” filter rods, “four-up” filter rods and “two-up” filter rodsthat are of the general format and configuration conventionally used forthe manufacture of filtered cigarettes can be handled usingconventional-type or suitably modified cigarette rod handling devices,such as tipping devices available as Lab MAX, MAX, MAX S or MAX 80 fromHauni-Werke Korber & Co. KG. See, for example, the types of devices setforth in U.S. Pat. No. 3,308,600 to Erdmann et al.; U.S. Pat. No.4,281,670 to Heitmann et al.; U.S. Pat. No. 4,280,187 to Reuland et al.;U.S. Pat. No. 4,850,301 to Greene, Jr. et al.; and U.S. Pat. No.6,229,115 to Vos et al.; and U.S. Pat. Application Publication Nos.2005/0103355 to Holmes, 2005/1094014 to Read, Jr., and 2006/0169295 toDraghetti, each of which is incorporated herein by reference.

Manners and methods for incorporating degradable particles and/orsuperabsorbent objects into desired regions of the filter element canvary. The particles can be incorporated into a polymeric material priorto fiber formation, incorporated into the fibrous filter materialsduring the fiber formation process, or incorporated into the fibrous towduring the rod-forming process.

For example, the particles and/or superabsorbent objects could beintroduced into the cellulose acetate or polyolefin “dope” prior tospinning the cellulose acetate or polyolefin fibers. For degradableparticles, starch particles may be admixed into the fiber precursorsolution. In such an embodiment, the particles are preferably insolublein the dope solvent (e.g., acetone) and instead form a slurry ordispersion in the liquid composition. Alternatively, the particles canbe soluble in the dope solvent. Still further, the degradable particlescould be dry-blended with the polymer (e.g., polypropylene or celluloseacetate) prior to fiber formation, such as by using a twin-screwextruder conventionally used to mix additives with polymeric materials.U.S. Pat. No. 6,136,246 to Rauwendaal et al., which is incorporated byreference herein, discloses an exemplary screw extruder that could beused to mix degradable particles and/or superabsorbent objects with apolymer material prior to fiber formation. One advantage ofincorporating the particles into the fibers prior to, or during, fiberformation is that each individual fiber that forms the fibrous towfilter material will have a plurality of degradable particles dispersedand imbedded therein, which may enhance degradation of the filterelement produced using the fibers. The amount of degradable particlesadded to the fiber precursor solution or admixed with a polymericmaterial using a dry-blending technique is typically in the range ofabout 5 to about 40% by weight, more often about 10 to about 30% byweight, based on the total weight of the precursor solution or totalweight of the blended components.

In another method, particulate materials (including superabsorbentobjects) can be incorporated into “dalmation” types of filter regionsusing the general types of techniques used to add particulate materialin traditional dalmation filter manufacture. Techniques for productionof dalmation filters are known, and representative dalmation filtershave been provided commercially by Filtrona Greensboro Inc.Alternatively, any other known types of techniques and equipment forproducing filter segments incorporating granular materials can besuitably altered so as to introduce degradable particles and/orsuperabsorbent objects into regions of filter segments. Unlikesuperabsorbent objects, degradable particles can be applied to thefibrous tow as a slurry in a suitable solvent (e.g., water). However,either may be added as free-flowing particulates. The particles can alsobe applied within a binder or adhesive matrix, or attached to a carriermaterial, such as a carrier fiber or capsule, and inserted into thefibrous tow with the carrier material. In certain alternativeembodiments, the degradable particles and/or superabsorbent objects(when the latter are initially presented in smaller, particulate-rangesizes) can be introduced to the inner surface of the plug wrap or withinthe side seam adhesive formulation. Exemplary processes for introducingadditives into fibrous filter tow during filter rod formation are setforth in U.S. Pat. Application Publication Nos. 2008/0029118 to Nelsonet al. and 2008/0302373 to Stokes et al., as well as in U.S. applicationSer. No. 12/124,891 filed May 21, 2008; Ser. No. 12/259,838 filed Oct.28, 2008; and Ser. No. 12/407,260 filed Mar. 19, 2009, all of which areincorporated by reference herein in their entirety.

Filter elements of the present invention can be incorporated within thetypes of cigarettes set forth in U.S. Pat. No. 4,756,318 to Clearman etal.; U.S. Pat. No. 4,714,082 to Banerjee et al.; U.S. Pat. No. 4,771,795to White et al.; U.S. Pat. No. 4,793,365 to Sensabaugh et al.; U.S. Pat.No. 4,989,619 to Clearman et al.; U.S. Pat. No. 4,917,128 to Clearman etal.; U.S. Pat. No. 4,961,438 to Korte; U.S. Pat. No. 4,966,171 toSerrano et al.; U.S. Pat. No. 4,969,476 to Bale et al.; U.S. Pat. No.4,991,606 to Serrano et al.; U.S. Pat. No. 5,020,548 to Farrier et al.;U.S. Pat. No. 5,027,836 to Shannon et al.; U.S. Pat. No. 5,033,483 toClearman et al.; U.S. Pat. No. 5,040,551 to Schlatter et al.; U.S. Pat.No. 5,050,621 to Creighton et al.; U.S. Pat. No. 5,052,413 to Baker etal.; U.S. Pat. No. 5,065,776 to Lawson; U.S. Pat. No. 5,076,296 toNystrom et al.; U.S. Pat. No. 5,076,297 to Farrier et al.; U.S. Pat. No.5,099,861 to Clearman et al.; U.S. Pat. No. 5,105,835 to Drewett et al.;U.S. Pat. No. 5,105,837 to Barnes et al.; U.S. Pat. No. 5,115,820 toHauser et al.; U.S. Pat. No. 5,148,821 to Best et al.; U.S. Pat. No.5,159,940 to Hayward et al.; U.S. Pat. No. 5,178,167 to Riggs et al.;U.S. Pat. No. 5,183,062 to Clearman et al.; U.S. Pat. No. 5,211,684 toShannon et al.; U.S. Pat. No. 5,240,014 to Deevi et al.; U.S. Pat. No.5,240,016 to Nichols et al.; U.S. Pat. No. 5,345,955 to Clearman et al.;U.S. Pat. No. 5,396,911 to Casey, III et al.; U.S. Pat. No. 5,551,451 toRiggs et al.; U.S. Pat. No. 5,595,577 to Bensalem et al.; U.S. Pat. No.5,727,571 to Meiring et al.; U.S. Pat. No. 5,819,751 to Barnes et al.;U.S. Pat. No. 6,089,857 to Matsuura et al.; U.S. Pat. No. 6,095,152 toBeven et al; and U.S. Pat. No. 6,578,584 to Beven; which areincorporated herein by reference. Still further, filter elements of thepresent invention can be incorporated within the types of cigarettesthat have been commercially marketed under the brand names “Premier” and“Eclipse” by R. J. Reynolds Tobacco Company. See, for example, thosetypes of cigarettes described in Chemical and Biological Studies on NewCigarette Prototypes that Heat Instead of Burn Tobacco, R. J. ReynoldsTobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p.1-58 (2000); which are incorporated herein by reference.

Cigarette rods typically are manufactured using a cigarette makingmachine, such as a conventional automated cigarette rod making machine.Exemplary cigarette rod making machines are of the type commerciallyavailable from Molins PLC or Hauni-Werke Korber & Co. KG. For example,cigarette rod making machines of the type known as MkX (commerciallyavailable from Molins PLC) or PROTOS (commercially available fromHauni-Werke Korber & Co. KG) can be employed. A description of a PROTOScigarette making machine is provided in U.S. Pat. No. 4,474,190 toBrand, at col. 5, line 48 through col. 8, line 3, which is incorporatedherein by reference. Types of equipment suitable for the manufacture ofcigarettes also are set forth in U.S. Pat. No. 4,781,203 to La Hue; U.S.Pat. No. 4,844,100 to Holznagel; U.S. Pat. No. 5,131,416 to Gentry; U.S.Pat. No. 5,156,169 to Holmes et al.; U.S. Pat. No. 5,191,906 to Myracle,Jr. et al.; U.S. Pat. No. 6,647,870 to Blau et al.; U.S. Pat. No.6,848,449 to Kitao et al.; and U.S. Pat. No. 6,904,917 to Kitao et al.;and U.S. Pat. Application Publication Nos. 2003/0145866 to Hartman;2004/0129281 to Hancock et al.; 2005/0039764 to Barnes et al.; and2005/0076929 to Fitzgerald et al.; each of which is incorporated hereinby reference.

The components and operation of conventional automated cigarette makingmachines will be readily apparent to those skilled in the art ofcigarette making machinery design and operation. For example,descriptions of the components and operation of several types ofchimneys, tobacco filler supply equipment, suction conveyor systems andgarniture systems are set forth in U.S. Pat. No. 3,288,147 to Molins etal.; U.S. Pat. No. 3,915,176 to Heitmann et al.; U.S. Pat. No. 4,291,713to Frank; U.S. Pat. No. 4,574,816 to Rudszinat; U.S. Pat. No. 4,736,754to Heitmann et al. U.S. Pat. No. 4,878,506 to Pinck et al.; U.S. Pat.No. 5,060,665 to Heitmann; U.S. Pat. No. 5,012,823 to Keritsis et al.and U.S. Pat. No. 6,360,751 to Fagg et al.; and U.S. Pat. PublicationNo. 2003/0136419 to Muller; each of which is incorporated herein byreference. The automated cigarette making machines of the type set forthherein provide a formed continuous cigarette rod or smokable rod thatcan be subdivided into formed smokable rods of desired lengths.

Preferred cigarettes of the present invention exhibit desirableresistance to draw. For example, an exemplary cigarette exhibits apressure drop of between about 50 and about 200 mm water pressure dropat 17.5 cc/sec. air flow. Preferred cigarettes exhibit pressure dropvalues of between about 60 mm and about 180, more preferably betweenabout 70 mm to about 150 mm, water pressure drop at 17.5 cc/sec. airflow. Typically, pressure drop values of cigarettes are measured using aFiltrona Cigarette Test Station (CTS Series) available from FiltronaInstruments and Automation Ltd.

Those of skill in the art will appreciate that embodiments not expresslyillustrated herein may be practiced within the scope of the presentinvention, including that features described herein for differentembodiments may be combined with each other and/or with currently-knownor future-developed technologies while remaining within the scope of theclaims presented here. It is therefore intended that the foregoingdetailed description be regarded as illustrative rather than limiting.And, it should be understood that the following claims, including allequivalents, are intended to define the spirit and scope of thisinvention.

1. A filter material configured for use as part of a smoking article,comprising: at least one segment of fibrous tow at least onedegradation-enhancing object, the degradation-enhancing objectconfigured to be activated by contact with moisture in a disposalenvironment.
 2. The filter material of claim 1, wherein the at least onedegradation-enhancing object comprises a superabsorbent materialconfigured to volumetrically expand upon contact with moisture andthereby to exert mechanical force against the fibrous tow.
 3. The filtermaterial of claim 2, wherein the superabsorbent material comprises amaterial selected from the group consisting of sodium polyacrylate)polyacrylamide copolymer, ethylene maleic anhydride copolymer,cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymer,cross-linked polyethylene oxide, hydrogel, starch-grafted copolymer ofpolyacrylonitrile, polyacrylate with poly(ethylene glycol),alginate-poly(sodium acrylate-coacrylamide), alginate-g-poly(sodiumacrylate)/kaolin, carboxymethylchitosan-g-poly(acrylic acid) copolymer,copolymerizate of acrylic acid and maleic anhydride,polyvinylalcohol-phosphate, acrylic acid-polyvinyl alcohol copolymer,polyacrylamide, acrylamide/N-vinyl-pyrrolidone/3(2-hydroxyethylcarbamoyl)acrylic acid, poly(acrylamide-co-methyl methacrylate),polyacrylamide/sodium alginate, polyacrylic acid, poly(sodium acrylate)cross-linked with modified poly(ethylene glycol), sulfonatedpolystyrene, hydrolysed acrylonitrile sulfonated polystyrene,poly(ethylene oxide), n-vinyl-2-pyrrolidone with partially neutralizedacrylic acid, poly(tartaramide)s, poly(ester-amide)s with oxyethylenesegments, poly(aspartic acid), poly(aspartic acid) derivative,poly(acrylic acid)/attapulgite/sodium humate, and any combinationthereof.
 4. The filter material of claim 2, wherein the superabsorbentmaterial is configured as a selected one of a capsule, pellet, orthread.
 5. The filter material of claim 2, wherein the superabsorbentmaterial is configured, dimensioned, and disposed such that volumetricexpansion thereof will spread apart the filter material.
 6. The filtermaterial of claim 1, further comprising at least one of plug wrapmaterial and tipping material circumscribing the fibrous tow.
 7. Thefilter material of claim 6, wherein the degradation-enhancing object isdisposed between the fibrous tow and the circumscribing material.
 8. Thefilter material of claim 1, wherein the fibrous tow comprises aplurality of individual filaments, and wherein a plurality ofdegradation-enhancing objects are disposed between the individualfilaments.
 9. The filter material of claim 1, wherein the at least onedegradation-enhancing object comprises a coating.
 10. The filtermaterial of claim 9, wherein the coating is configured to be disruptableby moisture.
 11. The filter material of claim 1, wherein the fibrous towcomprises cellulose acetate tow, polyolefin tow, or a combinationthereof.
 12. A filter element for a smoking article comprising one ormore segments of fibrous tow filter material according to claim
 1. 13.The filter element of claim 12, comprising a first segment of fibroustow filter material and a second segment of fibrous tow filter material,wherein the first segment of fibrous tow filter material comprises asuperabsorbent material and the second segment is devoid ofsuperabsorbent material.
 14. The filter material of claim 1, furthercomprising at least one degradability-promoting feature selected fromthe group consisting of microbial agents, cellulase, and fungal agents.15. A cigarette comprising: a tobacco rod having a smokable fillermaterial contained within a circumscribing wrapping material and afilter element connected to the tobacco rod at one end of the tobaccorod, said filter element comprising at least one segment of fibrous towhaving at least one degradation-enhancing object disposed therein, thedegradation-enhancing object configured to be activated by contact withwater.
 16. The cigarette of claim 15, wherein the at least onedegradation-enhancing object comprises a superabsorbent materialconfigured to volumetrically expand upon contact with moisture andthereby to exert mechanical force against the fibrous tow sufficient todisperse the fibrous tow.
 17. The cigarette of claim 16, wherein thesuperabsorbent material comprises a material selected from the groupconsisting of sodium polyacrylate) polyacrylamide copolymer, ethylenemaleic anhydride copolymer, cross-linked carboxy-methyl-cellulose,polyvinyl alcohol copolymer, cross-linked polyethylene oxide, hydrogel,starch-grafted copolymer of polyacrylonitrile, polyacrylate withpoly(ethylene glycol), alginate-poly(sodium acrylate-coacrylamide),alginate-g-poly(sodium acrylate)/kaolin,carboxymethylchitosan-g-poly(acrylic acid) copolymer, copolymerizate ofacrylic acid and maleic anhydride, polyvinylalcohol-phosphate, acrylicacid-polyvinyl alcohol copolymer, polyacrylamide,acrylamide/N-vinyl-pyrrolidone/3(2-hydroxyethyl carbamoyl)acrylic acid,poly(acrylamide-co-methyl methacrylate), polyacrylamide/sodium alginate,polyacrylic acid, poly(sodium acrylate) cross-linked with modifiedpoly(ethylene glycol), sulfonated polystyrene, hydrolysed acrylonitrilesulfonated polystyrene, poly(ethylene oxide), n-vinyl-2-pyrrolidone withpartially neutralized acrylic acid, poly(tartaramide)s,poly(ester-amide)s with oxyethylene segments, poly(aspartic acid),poly(aspartic acid) derivative, poly(acrylic acid)/attapulgite/sodiumhumate, and any combination thereof.
 18. The cigarette of claim 16,wherein the superabsorbent material is configured as a selected one of acapsule, pellet, or thread.
 19. The cigarette of claim 16, furthercomprising at least one of plug wrap material and tipping materialcircumscribing the fibrous tow, and where the mechanical force issufficient to disrupt the at least one plug wrap material and/or tippingmaterial.
 20. The cigarette of claim 15, wherein the at least onedegradation-enhancing object is disposed in a location selected from thegroup consisting of: between fibers of the fibrous tow, between thefibrous tow and an overlying wrapping material, between segments offibrous tow, and any combination thereof.
 21. The cigarette of claim 20,wherein the at least one degradation-enhancing object comprises acoating.
 22. The cigarette of claim 21, wherein the coating isconfigured to be disruptable by moisture.
 23. The cigarette of claim 21,wherein the fibrous tow comprises cellulose acetate tow, polyolefin tow,or a combination thereof.
 24. A cigarette including a filter configuredto degrade at an enhanced rate in a disposal environment where moistureis contacted, the cigarette comprising: a tobacco rod circumscribed by awrapping material; and a filter attached to the tobacco rod by a tippingmaterial, the filter comprising: a fibrous tow material circumscribed byplug wrap material contacting the tipping material; and at least onesuperabsorbent degradation-enhancing object contacting at least one ofthe tow material, the plug wrap material, and the tipping material, theobject configured to volumetrically expand upon contact with moisture ina disposal environment.
 25. The cigarette of claim 24, wherein thevolumetric expansion of the object is configured as sufficient to exertmechanical force against the fibrous tow that will disperse the fibroustow and disrupt at least a portion of the plug wrap, the tippingmaterial, or both the plug wrap and tipping material.
 26. The cigaretteof claim 24, wherein at least one of the plug wrap and the tipping paperfurther comprises a biodegradable adhesive.
 27. A cigarette including afilter configured to degrade at an enhanced rate in a disposalenvironment where moisture is contacted, the cigarette comprising: atobacco rod circumscribed by a wrapping material; and a filter attachedto the tobacco rod by a tipping material, the filter comprising: agathered web filters made using a selected one of paper, non-wovenfabric, or combination thereof, circumscribed by plug wrap materialcontacting the tipping material; and at least one superabsorbentdegradation-enhancing object contacting at least one of the towmaterial, the plug wrap material, and the tipping material, the objectconfigured to volumetrically expand upon contact with moisture in adisposal environment.